Self-sharpening knife

Abstract

A self-sharpening knife used inside an agricultural machine to cut and mix balls of hay or other food destined for animals consumption. The knife comprises a generally triangular steel plate whose base is right or rounded. The base is provided with a series of teeth, each of the teeth includes a pastille made of a material harder than steel and self-sharpening. The pastilles end by a cutting edge having a contour which forms the cutting edge of a tooth. The width of a pastille exceeds that of the steel and ends in a point which becomes round over cuts because of wear. The pastilles wearing out less quickly than steel thus causing that over cuts the width of the pastilles will always exceed the width of the steel. The pastilles cut until all their length and width are worn. The material of the pastille can be carbide or diamond.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A self-sharpening knife ( 20 , 42 , 46 , 50 ) comprising a steel plate ( 21 , 29 , 43 , 47 , 49 , 51 ) of a geometrical form, said plate comprises aligned along an end a series of teeth ( 26 , 26 ′,  26 ″, 26 ′″,  27 ) intended to cut, each one of said teeth comprises a thin pastille ( 27 ″,  30 , 32 , 34 , 58 ) of a material more cutting and harder than steel, said pastille is fixed at the steel part of said tooth, said pastille exceeds steel and ends in a cutting ( 52 , 52 ′) having a contour ( 54 ), said contour forming the cutting edge of said tooth, over the cuttings said cutting edge becomes minimally round by keeping a thin diameter, the maximum diameter of said round corresponds to the thickness of said thin pastille, said minimal round allows said cutting edge remaining cutting; said steel of said tooth wears simultaneously and more quickly because it is less harder than said pastille, so said pastille will always exceed said steel part and will cut until it is worn overall its length and all its width, said knife comprises also means of fastener used to fix it at an agricultural machine. 
     
     
         2 . The self-sharpening knife of  claim 1  wherein said steel plate has a thickness ranging between 3/16 and ½ po. 
     
     
         3 . The self-sharpening knife of  claim 2  wherein said thin pastille has a thickness ranging between 1/32 and ⅛ po. 
     
     
         4 . The self-sharpening knife of any one of  claims 1  to  3  wherein said teeth are disposed according to different angles along said end of said self-sharpening knife. 
     
     
         5 . The self-sharpening knife of any one of  claims 1  to  4  wherein said pastille is disposed with an angle ( 30 ) on the top face ( 22 ′) of said each tooth ( 26 ) and oriented pointing downwards of said knife to protect said steel part by preventing premature wear, said contour of said pastille is a cutting point ( 36 ), said pastille always exceeds said part of steel of said tooth. 
     
     
         6 . The self-sharpening knife of any one of  claims 1  to  5  wherein said pastille is disposed in sandwich ( 32 ) in the middle of each tooth ( 26 ′) and fixed in an encavure ( 44 ′) made in the steel ( 22 ″), said contour is a sharpened point ( 40 ) which exceeds steel to cut. 
     
     
         7 . The self-sharpening knife of any one of  claims 1  to  6  wherein said pastille is positioned straight ( 34 ) on the top of each tooth ( 26 ″), disposed parallel to said steel part, and ends into said cutting ( 52 ). 
     
     
         8 . The self-sharpening knife of any one of  claims 1  to  7  wherein each one of said teeth has the shape of a pointed triangle ( 26 ′″) having two side faces, said pastille is of a rectangular form ( 58 ), said pastille constituting one of the two sides faces extending from top ( 56 ) to the base of said triangle, at the time of the cutting the elements to be cut are directed directly vis-a-vis said pastilles, thus makes possible to cut more. 
     
     
         9 . The self-sharpening knife of any one of  claims 1  to  8  wherein each one of said tooth has a triangular form ( 27 ) ending in a point, said tooth comprises a bottom part made of steel ( 27 ′) and a triangular pastille ( 27 ″) forming the top part of said triangle, said pastille is made of a material harder than steel. 
     
     
         10 . The self-sharpening knife of any one of  claims 1  to  9  wherein said steel plate is of a generally triangular form, said series of teeth is located along the base of said triangle, said means of fasteners are holes ( 28 ) made in said plate and being used to fix said self-sharpening knife to said agricultural machine. 
     
     
         11 . The self-sharpening knife of  claim 10  wherein said triangle of said steel plate is truncated on its height and it comprises a vertical fold on the segment joining the apex of said truncated triangle, said fold being used to attach said knife to said agricultural machine and to have various angles of attack of said series of teeth. 
     
     
         12 . The self-sharpening knife of  claim 10  or  11  wherein said base is straight ( 24 ). 
     
     
         13 . The self-sharpening knife of  claim 10  or  11  wherein said base is convex ( 25 ), with this convex disposition said teeth are in attack, they are aligned the ones after the others and the cutting puts equal pressure on each one of said teeth, thus conferring to said convex knife a more regular and constant cut because said teeth wear simultaneously. 
     
     
         14 . The self-sharpening knife of  claim 10  or  11  wherein said base is concave ( 48 ). 
     
     
         15 . The self-sharpening knife of  claim 10  or  11  wherein said base forms a half-circle ( 50 ). 
     
     
         16 . The self-sharpening knife of any one of  claims 1  to  15  wherein said thin pastille is a carbide. 
     
     
         17 . The self-sharpening knife of any one of  claims 1  to  16  wherein said agricultural machine is a mixer. 
     
     
         18 . The self-sharpening knife of any one of  claims 1  to  17  wherein said steel constituting said self-sharpening knife is a hardened steel who has a heat treatment, said hardened steel wears less quickly than an ordinary steel not hardened, thus avoiding the exposition to impacts of said cutting edge, said cutting edge will then better cut. 
     
     
         19 . The self-sharpening knife of any one of  claims 1  to  18  wherein said pastille is fixed in an encavure made in the steel which has the same form as said pastille. 
     
     
         20 . The self-sharpening knife of  claim 19  wherein said fixing is silver brazing.